Aperture controlled electrostatic image reproduction

ABSTRACT

The invention basically comprises apparatus and methods relating to the field of electrostatics, and is concerned with electrostatic reproducing or constituting. Apertured screen means carry charge distributions in accordance with a pattern such that particles directed at the screen means pass therethrough under modulation control dictated by the pattern.

United States Patent 1191 Pressman et al.

[ APERTURE CONTROLLED ELECTROSTATIC IMAGE REPRODUCTION Inventors: Gerald L. Pressman, San Jose;

Thomas D. Kittredge, South San Francisco, both of Calif.

Assignee: Electroprint, Inc., Palo Alto, Calif.

Filed: Jan. 5, 1972 Appl. No.: 215,511

Related U.S. Application Data Division of Ser. No. 776,146, Nov. 15, 1968, Pat. No. 3,647,291.

U.S. c1. 346/74 P, 250/324, 355/16 1111. C1. G03g 5/04, 003 7/00 Field 61 Search 355/3, 16, 17; 118/637; 117/175; 101/010. 13; 96/14, 1.5, 1 R; 346/74 ES, 74 P; 250/324 References Cited 'UNITED STATES PATENTS 3,460,156 8/1969 Byrd 346/74 ES Jan. 22, 1974 3,339,469 9/1967 McFarlane, Jr 355/3 3,228,029 1/1966 McNaney 346/74 P 3,645,614 2/1972 McFarlane, Jr 355/3 3,582,206 6/1971 Burdige 346/74 ES 3,594,162 7/1971 Simm 346/74 ES 3,625,604 l2/l97l Pressman 355/3 3,277,818 10/1966 C0116 346/74 ES Pn'mary Examiner-Bernard Konick Assistant Examiner-Jay P. Lucas Attorney, Agent, or Firm-Wilfred G. Caldwell [57] ABSTRACT The invention basically comprises apparatus and methods relating to the field of electrostatics, and is concerned with electrostatic reproducing or constituting. Apertured screen means carry charge distributions in accordance with a pattern such that particles directed at the screen means pass therethrough under modulation control dictated by the pattern.

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1. Apparatus for controlling the flow of charged particles along a path comprising, charge supporting means, apertured for particle passage, interposed in said path; means for establishing a first electric field effective at the charge supporting means within the apertures thereof and so polarized as to prevent movement of particles along the path via the apertures; and electric field means for selectively, aperture by aperture, counteracting said first electric field by diminishing, cancelling, and partly and wholly reversing it within the apertures thereof to enable selective movement of charged particles along the path via selected apertures.
 2. The apparatus of claim 1 wherein the magnitude of said counteracting electric field is greater than the magnitude of said first electric field.
 3. The apparatus of claim 2 wherein the apertured means comprises a plurality of uniformly distributed apertures through a charge supportable layer for particle flow, and said fields are manifested as lines of force effective in said apertures selectively to aid and inhibit particle flow.
 4. The apparatus of claim 2 further comprising a source of toner particles for flow along said path.
 5. The apparatus of claim 2 further comprising a source of ions for flow along said path.
 6. Apparatus for controlling the flow of electrostatically charged particles along a path comprising, apertured electrostatic modulator means in said path and characterized by insulation properties for supporting electrical charge distribution; means for uniformly establishing electric fields effective within the apertures of the modulator means and so polarized as to permit movement of particles of one sign along the path through the modulator means via said apertures; and electric field means effective at the modulator means for selectively manifesting oppositely polarized electric fields in said apertures to diminish, cancel, and reverse said first electric fields, aperture by aperture, to prevent movement of charged particles along the path via selected apertures.
 7. The apparatus of claim 6 wherein said electric field means comprises means for establishing a second electric field having a polarity opposite from and a magnitude substantially twice the magnitude of said electric fields so as to counteract said fields, and means selectively discharging said fields. 